Triphenylboron-amine compounds and triphenylboron-pyridine (TPBP), in particular, are known to be effective biocides and marine anti-fouling agents and are, therefore, commercially important compounds. U.S. Pat. No. 3,211,679, for example, describes antifouling compositions comprising triphenylboraneamine complexes which provide good protection from marine fouling.
One method for producing TPBP is by the reaction of aqueous triphenylboron-NaOH adduct (NaΦ3BOH or TPBA) or triphenylboron-KOH adduct with pyridine in aqueous solution as shown in JP Publication No. 08-311074 (Yoshitomi Pharm Ind KK). Solid TPBP particles precipitate out with the progress of the reaction which can be from 30 minutes up to two days.
However, the particles formed by the above process are often of irregular shape and of undesirable particle size distribution to the extent that recovery of the solid particles using solid-liquid separation and drying methods can be difficult. It would thus be desirable to have a process that would produce solid TPBP particles of generally round, i.e., spherical, shape having a mean diameter greater than about 20 microns and a Gaussian particle size distribution that can be more efficiently recovered using available solid-liquid separation and drying methods. The present invention provides such a process that can be implemented on a commercial scale.